1. Field of the Invention
The present invention generally relates to a broadcast distribution technique, and particularly relates to broadcast distribution via an Internet protocol (IP) network.
2. Description of the Related Art
Television broadcast programs, radio broadcast programs and the like are typically distributed by radio waves. The advantage of distributing the broadcast programs by radio waves is that users located at different locations can view the same program at the same time.
However, in recent years, with developments in network technology, there is an increasing demand for a broadcasting scheme other than the conventional radio-wave-based distribution.
For example, Japanese Patent Application Laid-open No. 2006-25278 discloses a mobile terminal capable of directly receiving broadcast programs from a television network. However, due to some reasons if it is difficult to directly receive a broadcast program from a television station, the mobile terminal receives the broadcast program from a base station instead of the television station. On the other hand, Japanese Patent Application Laid-open No. H11-355854 discloses an on-vehicle broadcast receiving device capable of selectively receiving information required to operate or drive the vehicle from among information broadcast from a base station.
It is economically or due to other reasons difficult to newly establish a transmission medium that can replace the radio-wave-based distribution. Therefore, it is cost effective to use an existing transmission medium such as the Internet.
However, the Internet has a drawback that the bandwidth required for data delivery and the time required until arrival of data to a terminal cannot be guaranteed. In other words, delay can occur when a broadcast program is distributed via the Internet network to two different terminals using the conventional technology. As a result, it is almost impossible to use the Internet to perform simultaneous broadcasting (simulcasting).
Furthermore, distribution of a broadcast program, e.g., television broadcasting, includes sending of a large amount of data via a network. As a result, a huge workload is exerted on the network.